the tornado is blamed for 34 deaths in indiana and kentucky. the tornado was classified as devastating and winds were estimated between 206 and 270 miles-per-hour. >>> a blast in san francisco's financial district caused some worries today when an underground explosion blew a manhole cover into the air at grant and california streets. pg&e believes some sort of equipment failure caused the explosion. nobody was hurt but according to san francisco'ed, the manhole cover blew into pieces. >> when we got here we diverted traffic, and then smoke started coming from another manhole cover 25 yards east of that, around the corner of california and grant. >> there have been more than a dozen underground explosions in san francisco the past five years. pg&e points out it has been installing new manhole covers designed to release underground pressure without blasting into the air after a 2005 incident that receive rearly injured a pedestrian. >>> everybody is going green today. up next a look how san francisco celebrates st. patrick's day. >>> blown to bi